Telescopic anti-buckling guide system

ABSTRACT

A technique improves the ability to inject coiled tubing at a variety of wells. A telescopic, anti-buckling guide is designed to support the coiled tubing to prevent buckling under operating loads. The telescopic, anti-buckling guide also facilitates connection to a variety of well control stacks of different heights without requiring vertical movement of the coiled tubing injector and without the need for pressure containment members in the guide.

BACKGROUND

Coiled tubing rigs rely on coiled tubing injectors to inject coiled tubing into a well. Generally, the bottom of the coiled tubing injector is mounted directly to a stripper assembly through which the coiled tubing moves prior to entering a well stack and the well. Attempts have been made to provide greater flexibility in the ability to connect a given coiled tubing injector to a variety of well stacks by using telescoping risers between the stripper assembly and the well stack. However, the use of telescoping risers incurs a high cost and a high level of active maintenance. Additionally, the telescoping risers are required to maintain wellbore pressure.

SUMMARY

In general, the present invention provides a system and method for improving the ability to inject coiled tubing at a variety of wells. The system and method utilize a telescopic, anti-buckling guide through which coiled tubing is moved before entering the stripper assembly and ultimately entering the well. The telescopic, anti-buckling guide is designed to support the coiled tubing to prevent buckling under operating loads. Additionally, the telescopic, anti-buckling guide facilitates connection to a variety of well control stacks of different heights without requiring vertical movement of the coiled tubing injector and without the need for pressure containment members in the guide.

BRIEF DESCRIPTION OF THE DRAWINGS

Certain embodiments of the invention will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:

FIG. 1 is a schematic front view of a telescopic, anti-buckling guide system, according to an embodiment of the present invention;

FIG. 2 is a side view of the telescopic, anti-buckling guide, according to an embodiment of the present invention;

FIG. 3 is an orthogonal view of a lower guide member of the telescopic, anti-buckling guide illustrated in FIG. 2, according to an embodiment of the present invention;

FIG. 4 is an orthogonal view of an upper guide member of the telescopic, anti-buckling guide illustrated in FIG. 2, according to an embodiment of the present invention; and

FIG. 5 is an exploded view of the telescopic, anti-buckling guide system, according to an embodiment of the present invention.

DETAILED DESCRIPTION

In the following description, numerous details are set forth to provide an understanding of the present invention. However, it will be understood by those of ordinary skill in the art that the present invention may be practiced without these details and that numerous variations or modifications from the described embodiments may be possible.

The present invention relates to a system and methodology for facilitating the injection of coiled tubing into a well. A telescopic, anti-buckling guide enables deployment of a coiled tubing injector head onto a well control stack without requiring vertical movement of the injector head. The telescopic character of the guide also enables adjustment of the distance between the coiled tubing injector and the well control stack which allows the injector head to be used with well control stacks of different heights without requiring vertical movement of the injector head. The guide also supports the coiled tubing and prevents buckling of the coiled tubing between the coiled tubing injector and a stripper assembly positioned at the top of a well control stack.

Generally, the telescopic, anti-buckling guide provides a conduit for directing the coiled tubing from the injector head without requiring pressure seals. All pressure containing equipment can be located within the well control stack which reduces the cost and simplifies the structure of the telescopic, anti-buckling guide. For example, the cost of manufacturing the guide is reduced, and there are no maintenance requirements that would otherwise be associated with pressure seals. By avoiding the need to contain pressure, the telescopic, anti-buckling guide also avoids the need for locks that would otherwise be necessary to prevent unwanted expansion of the guide when exposed to internal well pressure.

One embodiment of a guide system 10 is illustrated in FIG. 1 as positioned at a well site 12. In this example, guide system 10 comprises a telescopic, anti-buckling guide 14 connected between a coiled tubing injector 16 and a well stack, such as well control stack 18. In the embodiment illustrated, telescopic anti-buckling guide 14 is directly connected to a stripper assembly 20 positioned generally at the top of well control stack 18.

Well control stack 18 is positioned on a surface 22 above a well 24 having a wellbore 26. Well control stack 18 comprises pressure control equipment 28 to control the internal well pressure within wellbore 26 and to prevent unwanted passage of well fluids through well control stack 18. Pressure control equipment 28 may comprise one or more members that can form the desired pressure seals able to hold back the internal well pressure. For example, blowout preventers or other pressure seals can be used. In the embodiment illustrated, all pressure control and all pressure control equipment is located below telescopic, anti-buckling guide 14 in, for example, well control stack 18. Accordingly, telescopic, anti-buckling guide 14 can be manufactured without pressure seals.

Coiled tubing injector 16 is designed to deliver coiled tubing 30 (shown in dashed lines) into well 24. Pressure control equipment 28 can be used to form a seal with the coiled tubing 30 to prevent passage of internal well pressure. Furthermore, telescopic, anti-buckling guide 14 is sized to support coiled tubing 30 and to prevent buckling of the coiled tubing between the coiled tubing injector 16 and the well control stack 18, e.g. between coiled tubing injector 16 and stripper assembly 20. Guide 14 supports coiled tubing 30 against buckling when exposed to operating loads.

The telescopic capability enables guide 14 to be compressed or extended as necessary to enable the connection of stripper assembly 20 to a variety of well control stacks 18 of different heights without requiring vertical movement of coiled tubing injector 16. When a coiled tubing injection operation is completed or the coiled tubing injector 16 is to be moved to another well stack, the stripper assembly 20 can simply be uncoupled from well control stack 18. Once uncoupled, the stripper assembly 20 is lifted upwardly to compress telescopic, anti-buckling guide 14 so as to clear well control stack 18 without requiring vertical movement of coiled tubing injector 16. The coiled tubing injector 16, guide 14 and a stripper assembly 20 can then be moved to the next desired location.

One embodiment of telescopic, anti-buckling guide 14 is illustrated in FIG. 2. In this embodiment, guide 14 comprises an upper guide 32 and a lower guide 34 that are telescopically engaged. In the example illustrated, upper guide 32 and lower guide 34 are interlocking, sliding cylindrical tubes that slide over one another. For example, lower guide 34 may be sized to slidably receive upper guide 32 therein. However, upper guide 32 can be sized to slidably receive lower guide 34 within its interior; or upper guide 32 and lower guide 34 may be provided with other interlocking, telescopic configurations.

By way of example, lower guide 34 may comprise a body portion 36 that is tubular in shape and has a hollow interior 38 sized to slidably receive upper guide 32. As also illustrated in FIG. 3, lower guide 34 may further comprise a mount 40 that is configured for connection with stripper assembly 20. Mount 40 may be in the form of a mounting flange 42 that is attached to stripper assembly 20 by a suitable fastener mechanism, such as a threaded engagement, a plurality of threaded fasteners, one or more weldments, or a combination of mechanisms. Lower guide 34 further comprises an expanded housing 44 that may be located generally between mount 40 and body portion 36. Expanded portion 44 comprises a window 46 positioned to provide access to a portion of stripper assembly 20 when stripper assembly 20 is engaged with telescopic, anti-buckling guide 14. For example, window 46 can be used to provide access to stripper assembly retaining pins 48 (see FIG. 2). Additionally, lower guide 34 may comprise other features, such as a side connector 50 that can be used to facilitate movement and positioning of lower guide 34 and/or telescopic, anti-buckling guide 14.

By way of further example, upper guide 32 may comprise a body portion 52, as further illustrated in FIG. 4. In this embodiment, body portion 52 is generally tubular and includes a hollow interior 54. Body portion 52 is sized so that its outside diameter fits within the inside diameter defined by hollow interior 38 of lower guide body portion 36. Furthermore, hollow interior 54 is sized to support a coiled tubing 30 against buckling when coiled tubing 30 is moved through telescopic, anti-buckling guide 14. Upper guide 32 may further comprise a connector 56 that is configured for connection with coiled tubing injector 16. Connector 56 may comprise a flange 58 designed for connection to coiled tubing injector 16 by a suitable fastener mechanism, such as a threaded fastener end, a plurality of threaded fasteners, one or more weldments, or a combination of mechanisms.

As illustrated in the expanded view of FIG. 5, body portion 52 of upper guide 32 is slidably engaged with body portion 36 of lower guide 34 to form the main body of telescopic, anti-buckling guide 14. A retention ring or other mechanism 60 can be used to, for example, prevent inadvertent separation of upper guide 32 from lower guide 34 once combined. Additionally, a variety of guides, e.g. inserts, 62 can be used to selectively size the hollow interior of guide 14 according to the size of coiled tubing 30 that is to be delivered through telescopic, anti-buckling guide 14 and into well 24. A connection end 64 of stripper assembly 20 is inserted into the interior of the expanded portion 44 and exposed via window 46. In many operations, stripper assembly 20 is retained in engagement with telescopic, anti-buckling guide 14 during movement from one well stack to another.

Depending on a variety of factors, including well stack size and style, environment, coiled tubing injector type, and well operation performed, the size and configuration of telescopic anti-buckling guide 14 may vary. The telescopic characteristics can be achieved with a variety of upper and lower guides that are coupled together for selective expansion and contraction. The internal diameters of cylindrical style guides can be adjusted to accommodate different coiled tubing sizes, and a variety of inserts or other mechanisms can be used to provide the desired guidance of coiled tubing into well control stack 18 and well 24. Furthermore, the telescopic, anti-buckling guide 14 can be designed with ends configured for engagement with a variety of coiled tubing injectors and stripper assemblies.

Accordingly, although only a few embodiments of the present invention have been described in detail above, those of ordinary skill in the art will readily appreciate that many modifications are possible without materially departing from the teachings of this invention. Accordingly, such modifications are intended to be included within the scope of this invention as defined in the claims. 

1. A device to prevent buckling of coiled tubing between a coiled tubing injector head and a well control stack, comprising: a telescopic, anti-buckling guide having: an upper guide comprising a connector configured for engagement with the coiled tubing injector head, the upper guide also having a hollow interior sized for movement of coiled tubing therethrough; and a lower guide telescopically engaged with the upper guide and comprising a mount configured for attachment to a stripper assembly, the lower guide also having a hollow interior through which the coiled tubing moves while being supported against buckling.
 2. The device as recited in claim 1, wherein the connector on the upper guide comprises a flange.
 3. The device as recited in claim 1, wherein the mount on the lower guide comprises a mounting flange.
 4. The device as recited in claim 1, wherein the upper guide comprises an upper body portion and the lower guide comprises a lower body portion slidably engaged with the upper body portion, the upper body portion and the lower body portion cooperating to prevent buckling of coiled tubing passing therethrough.
 5. The device as recited in claim 4, wherein the upper body portion is slidably received within the lower body portion.
 6. The device as recited in claim 1, wherein the lower guide comprises an expanded housing having a window to provide access to the stripper assembly when connected.
 7. The device as recited in claim 1, further comprising the stripper assembly coupled to the telescopic, anti-buckling guide.
 8. A method, comprising: coupling a coiled tubing injector and a well control stack with a telescopic, anti-buckling guide; and running coiled tubing through the telescopic, anti-buckling guide such that the coiled tubing is supported against buckling.
 9. The method as recited in claim 8, further comprising removing the coiled tubing injector from the well without lifting the coiled tubing injector vertically.
 10. The method as recited in claim 8, further comprising forming a pressure seal below the telescopic, anti-buckling guide.
 11. The method as recited in claim 8, further comprising forming the telescopic, anti-buckling guide with a hollow lower guide slidably engaged with a hollow upper guide.
 12. The method as recited in claim 8, further comprising providing a window through a side wall of the telescopic, anti-buckling guide to provide access to a portion of the stripper assembly.
 13. A method, comprising: mounting a telescopic guide above all pressure containment equipment of a well control stack; and connecting a coiled tubing injector to the telescopic guide at an end of the telescopic guide generally opposite the well control stack.
 14. The method as recited in claim 13, further comprising injecting coiled tubing through the telescopic guide and into a well.
 15. The method as recited in claim 14, further comprising sizing the telescopic guide to support the coiled tubing against buckling under operating loads.
 16. The method as recited in claim 13, further comprising moving the telescopic guide between well control stacks of different heights without moving the coiled tubing injector vertically.
 17. The method as recited in claim 13, wherein mounting comprises coupling the telescopic guide to a stripper assembly.
 18. The method as recited in claim 17, further comprising removing the coiled tubing injector from the well by: disconnecting the stripper assembly from the well control stack; and lifting the stripper assembly to compress the telescopic guide without moving the coiled tubing injector vertically.
 19. A system, comprising: a well control stack positioned above the well and having a pressure containment member; a stripper assembly coupled to the well control stack; a telescopic guide coupled to the stripper assembly on an end generally opposite the well control stack, the telescopic guide being without pressure containment capability; and a coiled tubing injector positioned to inject coiled tubing through the telescopic guide and into the well.
 20. The system as recited in claim 19, wherein the telescopic guide is formed with interlocking, sliding, cylindrical tubes.
 21. The system as recited in claim 20, wherein the interior diameters of the interlocking, sliding, cylindrical tubes are selected to support the coiled tubing and to prevent it from buckling under load.
 22. The system as recited in claim 19, wherein the telescopic guide comprises an upper guide with a flange.
 23. The system as recited in claim 22, wherein the telescopic guide comprises a lower guide configured to slidably receive the upper guide, the lower guide comprising a mounting flange positioned to engage the stripper assembly.
 24. The system as recited in claim 23, wherein the lower guide comprises an expanded housing having a window to provide access to the stripper assembly when connected.
 25. The system as recited in claim 23, wherein the lower guide is tubular and sized to slidably receive the upper guide therein, the upper guide having a hollow interior sized to receive the coiled tubing therethrough. 